By Marwan Hamed, MPH
Screens! Whether we are scrolling through our phones, watching television, staring at our computer monitors, or engaging in a video call on a tablet, one thing is for certain: Screens have become a major part of our daily lives. In fact, you are almost surely looking at a screen right now to read this article. As with any form of white light, including sunlight — screens contains blue light harmful, and scientists have become concerned about the potential health effects of overexposure.
Blue light and the biological clock
Studies show that being overexposed to blue light, especially during the night hours can be harmful to our health. The main reason is that blue light exposure could be throwing off our natural biological clocks. Here we have a manmade environmental hazard that has spread globally. Blue light overexposure has been shown to have the most dramatic effects among people who are considered photophobic or hypersensitive to light, oftentimes leading to headaches and other symptoms.
The main problem with blue light
So what exactly is so risky about blue light?
The problems really start when we are staring at television and computer screens during the evening before bedtime and late into the night. This can lead our biological clocks into getting tricked! Our minds and bodies begin to behave as if we are still experiencing daylight hours and for many people, this will make it more difficult to maintain a healthy sleep schedule.
In the long run, poor sleep schedules have been shown to lead to a range of mental and physical health problems, including brain function impairment, heart problems, diabetes, obesity, and depression — to name a few.
Blue light can trigger migraines — extremely painful and throbbing headaches that can last hours at a time.
Photophobia — an extreme sensitivity to light that often accompanies a migraine. Photophobia and migraine can be caused by factors not directly related to blue light, including genetics, medications, and mental health. A study of 103 patients with migraines found that over 80% of the participants had photophobia. Wearing sunglasses may be the best natural way to manage light sensitivity and migraine. This simple yet effective technique can reduce blue light overexposure and the migraines caused by it.
There is a definite link between photophobia and migraines and there are several theories on how the two are related — including a focus on the nerves, cells in the eyes, and other possible pathways. One of the emerging theories is that photophobia in migraines could result from the light-based activation of eye-based pathways that have a major part to play in the body’s overall balancing mechanism used to maintain internal stability — homeostasis achieved by regulating blood pressure, body temperature, and blood sugar levels, to name a few.
Although this theory remains to be verified in lab studies, it suggests that the relationship between photophobia and migraines may be more complex than previously believed. Whatever the case may be, there is a known link between what happens to the eyes and how it affects the head.
With as many as 18% of women and 6% of men suffering from regular migraines and the majority of migraine sufferers experiencing increased sensitivity to light, it is important to try to manage these symptoms together — protect our eyes to protect our heads.
Beyond the effects on the biological clock, blue light has been shown to put a lot of strain directly on our eyes. These effects are so noticeable they have earned a spot in the medical literature to cover a group of symptoms related to electronic screen use — digital eye or computer vision syndrome, which includes blurred vision, headache, dry eyes, eye strain, and other physical ailments at or around the eyes.
Of course, the symptoms and severity differ from person to person depending on screen usage, age, and other factors. The most dramatic of the effects of overexposure to blue light may be the long term physical damage it causes some people, including damage to cells in the eyes that are responsible for receiving light.
Why not just block out blue light altogether?
Well, it’s not that simple!
Blue light isn’t necessarily a bad thing, in and of its own! In fact, it constitutes a very beneficial part of the visual light spectrum which can help us feel more energized and alert. And timed correctly, it stabilizes our circadian day-night cycle.
Research has looked into the effects of specifically blocking blue light while letting the rest of the light through. One randomized controlled study found that wearing lenses that blocked blue light for 3 hours before bedtime for 2 weeks showed improved sleep for adults with insomnia. And an animal study found that depriving gerbils of blue light led to an increase in depression-like symptoms. So, there is a delicate balance, keyed to the timing of blue light exposure across the day and night.
On one hand, we don’t want to be underexposed to light to the point that we become depressed. On the other hand, we want to be careful of how much we blue light we are exposed to especially at night because we need our sleep to be as mentally, physically, and emotionally healthy as we can make it.
So, what’s the takeaway?
If you or someone you know is struggling with any of the problems mentioned here, which could be related to being overexposed to blue light, then:
- limit your hours of screen use during the evening and night hours
- consider using blue-blocking light bulbs or glasses to reduce your exposure to blue light during the evening and night hours — or even during the day if you are plagued with migraines
- speak with a licensed health professional about your mental and physical health, to make sure that blue light exposure is what’s causing your symptoms.
Marwan Hamed is a public health practitioner and freelance writer for CET.